iqm session 1 5nov11

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IT Quality Management

Jeeshan George

Session 1

5th Nov, 2011

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Session plan

� Context Setting

� Product quality

� Service quality

� Situation room 1

� Quality by stages

� Quality paradigm

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Context Setting

� Expectations

� Some ground rules

� Ref material

� Evaluations

� … and some history

4

Session plan

� Context Setting

� Product quality

� Service quality




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8 Dimensions of product quality

• Performance

• Reliability

• Durability

• Serviceability

• Aesthetics

• Features

• Perceived Quality

• Conformance to standards

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Dimensions of product quality

Basic operating characteristics of a product

Intended functionality of the product

Example

How well a car is handled or its gas mileage

Performance

Probability that a product will operate properly within an

expected time frame

How often does the product fail?

Example

A TV will work without repair for about seven years

Reliability

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performance over a long period of time

How long will the product last?

Example

After the 3 yr warranty of Hyundai, how much longer will my

i10 work fine?

Durability

Ease of getting repairs, speed of repairs

How easy is it to repair the product?

Example

If amazon.com sends the wrong book, how hard is it to get

this error corrected?

Serviceability


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subjective perceptions based on brand name, advertising,

etc.

What is the reputation of the company selling this product?

Example

Toyota will never compromise on quality of its cars

Perceived quality

Degree to which a product meets pre–established standards

Is the product made as designed?

Example

Ritz is designed to give 18.1 km/lt, how much does it really

give you?

Conformance


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Session plan

� Context Setting

� Product quality

� Service quality




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7 Dimensions of service quality

• Timeliness

• Completeness

• Courtesy

• Consistency

• Convenience

• Accuracy

• Responsiveness

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Promptness of providing service as per customer’s need

How long must a customer wait for service, and is it

completed on time?

Example

Is a FedEx overnight package delivered overnight?

Timeliness

Extent of fulfilling customer’s request

Is everything customer asked for provided?

Example

Customer gives take away order, does the package contain

everything ordered?

Completeness

Dimensions of service quality

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Manner of providing service (customer facing agent)

how are customers treated by employees?

Example

Were the customer service rep patient in understanding

your problem?

Courtesy

Repeatability of good performance

Is same level of service provided to each customer each

time?

Example

Is your newspaper delivered on time every morning?

Consistency


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Ease of getting service

how easy is it to obtain service?

Example

Do you buy from Foodmart because is closer to your place?

Accessibility / Convenience

Are the details as actual each time?

Are they exact in what is being given to you?

Example

Do you have issues with your mobile bill each month?

Accuracy


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Time to 1st response

How well does company react to unusual situations?

Example

How long does the IVR take to get you connected?

Responsiveness


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outline

� Context Setting

� Product quality

� Service quality




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Situation Room 1

Just like there are Dimensions of Quality for ‘Products’ and ‘Services’,

If ‘Software’ was to be a different category, what should be the Dimensions of Software quality?

List out all the ones you think are important with examples of each.

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Dimensions of software quality

• Correctness

• Maintainability

• Portability

• Reusability

• Scalability

• Usability

• Reliability

• Integrity

• Interoperability

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Group Exercise

• G1: Myntra.com

• G2: ERP issue

• G3: World War III

• G4: Bulk SMS utility

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Session plan

� Context Setting

� Product quality

� Service quality




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Quality by stages

• Quality of Design

refers to the characteristics that designer’s specify for an item

o Materials/Components used

o Specifications of the components

o Reliability of drive train components

• Quality of conformance

is the degree to which the design specifications are followed during build

o Choice of processes

o Training of the people

o Quality-assurance procedures that were used

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Session plan

� Context Setting

� Product quality

� Service quality




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Variability

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Cost of Quality

• Cost of Quality

includes all costs incurred in the pursuit of quality or in performing quality related activities such as appraisal costs, failure costs and external failure costs

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Quality Assurance

• Quality Assurance

consists of processes, tools and techniques used to proactively eliminate causes of poor quality

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Need for Quality Assurance

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Acceptance Sampling

• Acceptance sampling is the inspection and classification of

a sample of the product selected at random from a larger

batch or lot and the ultimate decision about disposition of

the lot.

• Two types:

1. Outgoing inspection - follows production

2. Incoming inspection - before use in production

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Acceptance Sampling

A Sampling PlanSampling Plan simply requires two parameters to be determined:

• n the sample size (how many units to sample from a lot)

• c the maximum number of defective items that can be found in

the sample before the lot is rejected.

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Risks in Acceptance Sampling

RISKS for the producer and consumer in sampling plans:

• Acceptable Quality Level (AQL)

o Max. acceptable percentage of defectives defined by producer.

• αααα (Producer’s risk)

o The probability of rejecting a good lot.

• Lot Tolerance Percent Defective (LTPD)

o Percentage of defectives that defines consumer’s rejection point.

• ββββ (Consumer’s risk)

o The probability of accepting a bad lot.

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Acceptance Sampling

Advantages

• Economy

• Less handling damage

• Fewer inspectors

• Upgrading of the inspection job

• Applicability to destructive testing

• Entire lot rejection (motivation for

improvement)

Disadvantages

• Risks of accepting “bad” lots and

rejecting “good” lots

• Added planning and documentation

• Sample provides less information

than 100-percent inspection

• Reactive approach

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Statistical Quality Management/Control (SQC)

• SQC is a number of different techniques designed to evaluate quality

from a conformance view

o How are we doing in meeting specifications?

• SQC can be applied to both manufacturing and service processes

• SQC techniques usually involve periodic sampling of the process and

analysis of data

o Sample size

o Number of samples

• SQC techniques are looking for variance

• Most processes produce variance in output

o we need to monitor the variance (and the mean also) and correct

processes when they get out of range

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SQC premise

• A graph that establishes control limits of a process

• Control limits are set (upper and low bands)

11 22 33 44 55 66 77 88 99 1010Sample numberSample number

UpperUppercontrolcontrol

limitlimit

ProcessProcessaverageaverage

LowerLowercontrolcontrol

limitlimit

Out of controlOut of control

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SQC premise

• A process is in control if…

o … no sample points outside limits

o … most points near process average

o … about equal number of points above and below centerline

o … points appear randomly distributed

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Variation types

Random

• inherent in a process

• depends on equipment and

machinery, engineering,

operator, and system of

measurement

• natural occurrences

Non-Random

• special causes

• identifiable and correctable

• include equipment out of adjustment,

defective materials, changes in parts

or materials, broken machinery or

equipment, operator fatigue or poor

work methods, or errors due to lack

of training

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Attributes and Variables

• Attribute

o a product characteristic that can be evaluated with a discrete response

o good – bad; yes - no

• Variable

o a product characteristic that is continuous and can be measured

o weight - length

• Variables

• mean (x bar – chart)

• range (R-chart)

• Attributes

• p-chart

• c-chart

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Basic Stats

Mean

Normal Distributions have a mean (μ)

and a standard deviation (σ)

For a sample of N observations:

∑=

=N

i

iNxX

1

( )

N

Xx

N

i

i∑=

−

= 1

2

σ

where:

xi= Observed value

N = Total number of observed values

Standard Deviation

−3σ +3σ

99.7%

µ

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Session plan

� Recap of session 1

� Dimensions of product quality

� Dimensions of service quality




� Acceptance sampling

� Statistical Process Control (SPC)

� Attributes based measures

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P-chart

• Uses portion defective in a sample

UCL = p + zσσσσp

LCL = p - zσσσσp

z = number of standard deviations from

process average

p = sample proportion defective; an estimate

of process average

σσσσp= standard deviation of sample proportion

σσσσσσσσpp = = pp(1 (1 -- pp))

nn

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Construction of P-chart

20 samples of 100 pairs of jeans20 samples of 100 pairs of jeans

NUMBER OFNUMBER OF PROPORTIONPROPORTIONSAMPLESAMPLE DEFECTIVESDEFECTIVES DEFECTIVEDEFECTIVE

11 66 .06.06

22 00 .00.00

33 44 .04.04

:: :: ::

:: :: ::

2020 1818 .18.18

200200

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UCL = p + z = 0.10 + 3p(1 - p)

n

0.10(1 - 0.10)

100

UCL = 0.190

LCL = 0.010

LCL = p - z = 0.10 - 3p(1 - p)

n

0.10(1 - 0.10)

100

= 200 / 20(100) = 0.10total defectives

total sample observationsp =

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0.020.02

0.040.04

0.060.06

0.080.08

0.100.10

0.120.12

0.140.14

0.160.16

0.180.18

0.200.20

Pro

po

rtio

n d

efe

cti

ve

Pro

po

rtio

n d

efe

cti

ve

Sample numberSample number

22 44 66 88 1010 1212 1414 1616 1818 2020

UCL = 0.190

LCL = 0.010

p = 0.10

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C-chart

• uses number of defective items in a sample

UCL = UCL = cc + + zzσσσσσσσσcc

LCL = LCL = cc -- zzσσσσσσσσcc

where

c = number of defects per sample

σσσσσσσσcc = = cc

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C-chart

Number of defects in 15 sample roomsNumber of defects in 15 sample rooms

1 121 12

2 82 8

3 163 16

: :: :

: :: :15 15 1515

190190

SAMPLESAMPLE

cc = = 12.67= = 12.67190190

1515

UCLUCL = = cc + + zzσσσσσσσσcc

= 12.67 + 3 12.67= 12.67 + 3 12.67

= 23.35= 23.35

LCLLCL = = cc -- zzσσσσσσσσcc

= 12.67 = 12.67 -- 3 12.673 12.67

= 1.99= 1.99

NUMBER

OF

DEFECTS

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C-chart

33

66

99

1212

1515

1818

2121

2424

Nu

mb

er

of

defe

cts

Nu

mb

er

of

defe

cts

Sample numberSample number

22 44 66 88 1010 1212 1414 1616

UCL = 23.35

LCL = 1.99

c = 12.67

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Questions

Afterthoughts

[email protected]

iqm session 1 5nov11

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